1. Field of the Invention
This invention relates to convertible sewing machines in general, and more particularly to a latch and hinge arrangement in which a pivotally mounted supplemental work supporting surface is mounted to enable a machine to accommodate sewing material having a flat shape or sewing material generally tubular in shape.
2. Description of the Prior Art
Sewing machines are known in the prior art in which the base, or bed, is convertible to permit the sewing of flat or tubular material. One such machine is disclosed in U.S. Pat. No. 3,863,582 of Patricia et al. The lid disclosed in the Patricia et al. patent is fastened to the sewing machine base by a pair of cylindrical pins that pass through bosses on the lid and engage upstanding legs on the base. The lid has a spring-biased detent that engages a depression in the bed to retain the lid in a bridging position.
Other convertible bed sewing machines are known in which the lid must be slid away from the cylindrical portion of the bed to permit the sewing of tubular garments thereon. The necessity to remove the detachable lid to convert the machine from flat bed to cylinder bed operation and to replace the lid to convert the machine back to flat bed operation is, among other things, a bothersome inconvenience, especially when frequent conversions are made between flat and tubular sewing materials.
It is desirable to provide a sewing machine having a convertible bed that may be easily converted from a flat, expansive support surface to one which will accommodate tubular garments. The convertible bed configuration should be easily changed to the flat bed configuration by a minimum effort on the part of the sewing machine operator. It is also desirable to provide a convertible bed lid that may be easily manufactured and may be assembled from a minimum number of low tolerance parts.
One problem with prior known convertible bed lids is that they required the assembly of close tolerance parts to operate properly.
Another problem is that prior known convertible bed lids required separate fasteners, or latches, to support them in the raised position.
Still another problem is that some prior known lids were susceptible to being accidentally unlatched due to pressure of the operator's hand on the lid.